1. Field of the Invention
The present invention relates to a core bar for a rubber crawler and a rubber crawler used for a farm machine, a construction machine and the like and, to be more specific, to an outside rail type rubber crawler.
2. Description of the Related Art
In Japanese Examined Utility Model Publication No. HEI 7-17658, there is proposed a core bar for a rubber crawler having a pair of angular protruding parts (protrusions for preventing the coming-off of a rolling wheel) formed on both sides of an engaging part at the center between right and left wing parts, on outer side of each of the angular parts described above is formed a shoulder part (outside rail) elevated with respect to the wing parts of the core bar, wherein the respective shoulder parts are formed with overhanging parts that overhang in the front-rear direction (in the widthwise direction of the wing part), and wherein the top surfaces of the respective shoulder parts are slanted upward from the center to the end portions of the front and rear overhanging parts; and a crawler in which the core bars for a rubber crawler are embedded in a rubber crawler body with the top surfaces (rail surfaces) of the shoulder parts described above exposed on the inner circumferential surface of the rubber crawler so that the top surfaces of the shoulder parts form a rolling wheel track against which the outside collars of an outside collar type rolling wheel are abutted.
According to the related art described above, when the overhanging part is sunk, it is brought closer to an adjacent shoulder part (outside rail) in the circumferential direction (in the lengthwise direction) of the crawler to narrow the distance between the core bars, so that the rolling wheel track is made nearly continuous in the circumferential direction, thereby reducing vibrations as much as possible.
However, since the sinking of the overhanging part increases the height difference between the adjacent overhanging parts in the circumferential direction of the crawler and, when the rolling wheel is transferred to the next overhanging part, the rolling wheel collides with the next overhanging part causing noises and vibrations.
In particular, in a truck loader, a vibration roller, a bulldozer or the like, which mostly runs at comparatively high speeds, the collision of the rolling wheel with the overhanging parts tends to cause large noises and damages the overhanging part or the rolling wheel.